build: don't mandate availability of a fetcher program

It is common that build hosts are isolated from outside world. They
don't necessarily have wget or ftp installed.

Turn the error into warning in configure. And point FETCHER to `false'
command if neither wget nor ftp is available, so any attempt to
download will result in error.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>

m4/fetcher.m4

@@ -1,5 +1,6 @@
 AC_DEFUN([AX_CHECK_FETCHER], [
 AC_PATH_PROG([WGET],[wget], [no])
+AC_PATH_PROG([FALSE],[false], [/bin/false])
 AS_IF([test x"$WGET" != x"no"], [
     FETCHER="$WGET -c -O"
 ], [
@@ -7,7 +8,8 @@ AS_IF([test x"$WGET" != x"no"], [
     AS_IF([test x"$FTP" != x"no"], [
         FETCHER="$FTP -o"
     ], [
-        AC_MSG_ERROR([cannot find wget or ftp])
+        FETCHER="$FALSE"
+        AC_MSG_WARN([cannot find wget or ftp])
     ])
 ])
 AC_SUBST(FETCHER)

stubdom/configure

@@ -625,6 +625,7 @@ CFLAGS
 CC
 FETCHER
 FTP
+FALSE
 WGET
 CMAKE
 extfiles
@@ -2362,6 +2363,47 @@ $as_echo "no" >&6; }
 fi
 
 
+# Extract the first word of "false", so it can be a program name with args.
+set dummy false; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_path_FALSE+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  case $FALSE in
+  [\\/]* | ?:[\\/]*)
+  ac_cv_path_FALSE="$FALSE" # Let the user override the test with a path.
+  ;;
+  *)
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_path_FALSE="$as_dir/$ac_word$ac_exec_ext"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+  test -z "$ac_cv_path_FALSE" && ac_cv_path_FALSE="/bin/false"
+  ;;
+esac
+fi
+FALSE=$ac_cv_path_FALSE
+if test -n "$FALSE"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $FALSE" >&5
+$as_echo "$FALSE" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
 if test x"$WGET" != x"no"; then :
 
     FETCHER="$WGET -c -O"
@@ -2415,7 +2457,9 @@ fi
 
 else
 
-        as_fn_error $? "cannot find wget or ftp" "$LINENO" 5
+        FETCHER="$FALSE"
+        { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: cannot find wget or ftp" >&5
+$as_echo "$as_me: WARNING: cannot find wget or ftp" >&2;}
 
 fi
 

tools/configure

@@ -644,6 +644,7 @@ system_aio
 zlib
 FETCHER
 FTP
+FALSE
 WGET
 pixman_LIBS
 pixman_CFLAGS
@@ -8219,6 +8220,47 @@ $as_echo "no" >&6; }
 fi
 
 
+# Extract the first word of "false", so it can be a program name with args.
+set dummy false; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_path_FALSE+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  case $FALSE in
+  [\\/]* | ?:[\\/]*)
+  ac_cv_path_FALSE="$FALSE" # Let the user override the test with a path.
+  ;;
+  *)
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_path_FALSE="$as_dir/$ac_word$ac_exec_ext"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+  test -z "$ac_cv_path_FALSE" && ac_cv_path_FALSE="/bin/false"
+  ;;
+esac
+fi
+FALSE=$ac_cv_path_FALSE
+if test -n "$FALSE"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $FALSE" >&5
+$as_echo "$FALSE" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
 if test x"$WGET" != x"no"; then :
 
     FETCHER="$WGET -c -O"
@@ -8272,7 +8314,9 @@ fi
 
 else
 
-        as_fn_error $? "cannot find wget or ftp" "$LINENO" 5
+        FETCHER="$FALSE"
+        { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: cannot find wget or ftp" >&5
+$as_echo "$as_me: WARNING: cannot find wget or ftp" >&2;}
 
 fi